Short definition
A secondary fermentation where bacteria convert sharp malic acid into softer lactic acid, giving wine a creamier texture.
Malolactic fermentation is not really fermentation — it is a bacterial conversion. Think of it as swapping green-apple tartness for cream. Almost every red wine undergoes it. For whites, it is optional: a buttery Napa Chardonnay has had full malo, while a razor-sharp Chablis has been blocked from it entirely. Same grape, opposite textures.